Spectrally sensitized silver halide photographic emulsion

ABSTRACT

A SPECTRALLY SENSITIZED SILVER HALIDE PHOTOGRAPHIC EMULSION CONTAINING AT LEAST ONE SENSITIZING DYE REPRESENTED BY THE FOLLOWING FIRST FORMULA:   1-R3,2-((1-R4,3-R2,4,5-(-Z2-)IMIDAZOLIN-2-YL)=CH-CH=CH-),   3-R1,4,5-(-Z1-)IMIDAZOLIUM (X1-)P-1   WHEREIN R1, R2, AND R4 EACH REPRESENT ALKYL GROUPS, AT LEAST ONE OF SAID R3 AND R4 BEING AN ALKYL GROUP HAVING A SULFO GROUP; Z1 AND Z2 REPRESENT THE NON-METALLIC ATOMIC GROUPS NECESSARY TO COMPLET A BENZIMIDAZOLE NUCLEUS; X1-REPRESENTS AN ACID ANION AND P REPRESENTS AN INTEGER OF 1 OR 2, P BEING 1 WHEN SAID DYE FORMS AN INTERMOLECULAR SALT; AND AT LEAST ONE SENSITIZING DYE REPRESENTED BY THE FOLLOWING SECOND FORMULA:   1-R5,2-(R6-N&lt;(-Z4-C(=CH-)-)),5,6-(-Z3-)PYRIDINIUM (X2-)Q-1   WHEREIN Z3 REPRESENTS THE ATOMIC GROUP NECESSARY TO COMPLETE A QUINOLINE NUCLEUS; Z4 REPRESENTS THE NONMETALLIC ATOMIC GROUP NECESSARY TO COMPLETE A BENZOTHIAZOLE OR BENZOSLENAZOLE NUCLEUS SUBSTITUTED BY A CARBOXYLIC ACID, AN ALKOXYCARBONYL, A CARBAMOYL, OR AN ACYL GRUP; R5 AND R6 REPRESENT ALKYL GRUPS, AT LEAST ONE OF SAID R5 AND R6 BEING AN ALKYL GROUP HAVING A SULFO GROUP; V2-REPRESENTS AN ACID ANION AND Q HAS THE SAME MEANING AS P.

United States Patent 3,666,480 SPECTRALLY SENSITIZED SILVER HALIDE PHOTOGRAPHIC EMULSION Keisuke Shiba, Akira Sato, and Tadashi Ideka, Ashigaramachi, Kanagawa, Japan, assignors to Fuji Photo Film (30., Ltd., Ashigara-machi, Kanagawa, Japan No Drawing. Filed Oct. 29, 1970, Ser. No. 85,229 Claims priority, application Japan, Oct. 29, 1969, 44/ 86,580 Int. Cl. G03c 1/14 US. Cl. 96124 9 Claims ABSTRACT OF THE DISCLOSURE A spectrally sensitized silver halide photographic emulsion containing at least one sensitizing dye represented by the following first Formula:

wherein R R R and R each represent alkyl groups, at least one of said R and R being an alkyl group having a sulfo group; Z and Z represent the non-metallic atomic groups necessary to complete a benzimidazole nucleus; X represents an acid anion and p represents an integer of 1 or 2, p being 1 when said dye forms an intermolecular salt; and at least one sensitizing dye represented by the following second Formula:

BACKGROUND OF THE INVENTION Field of the invention This invention relates to a spectrally sensitized silver halide photographic emulsion, in particular, one which is supersensitized in the green region.

Description of the prior art It is well known that spectral sensitization is a very important technique employed in the making of a silver halide photographic emulsion, in particular, a color photosensitive material. The spectral sensitivity depends on the chemical structure and property of the sensitizing dye used and the property of the silver halide used, for example, halogen composition, crystal habit, chemical ripening, pAg and pH. The spectral sensitivity, however, also depends on the various additives to the emulsion, many of which decrease the spectral sensitivity. In the case of an emulsion used in the making of an incorporated type color photographic material, the sensitivity is decreased by the introduction of a coupler. This efiect 3,666,480 Patented May 30, 1972 is a large obstacle in the making of photographic material.

The distribution of spectral sensitivity in the green region in which human eyesight sensitivity is high is very important for the color reproduction of a color photosensitive material. Therefore, many eiforts have been made directed toward spectral sensitization in the green region to obtain a suitable spectral sensitivity distribution as well as a high sensitivity. For instance, United States Pat. No. 2,701,198 discloses a method of sensitization comprising the combination of a benzimidazolocarbocyam'ne dye and a pseudocyanine dye. Japanese patent publication Nos. 4936/68 and 22884/68 disclose the combination of a benzimidazolocarbocyanine dye and a benzoxacarbocyanine dye. However, these methods still have great disadvantages. For example, in the method disclosed in United States Pat. No. 2,701,198, the sensitivity is lowered remarkably by the coexistence of the coupler and the dye contamination is increased. In the method disclosed in Japanese patent publication No. 4936/68, there is much dye contamination and the sensitivity is low in the relatively short wavelength region of 510-530 my. of the green region as evidenced by Japanese patent publication 22884/ 68.

SUMMARY OF THE INVENTION It is the principal object of this invention to provide a spectrally sensitized silver halide photographic emulsion in which the sensitivity in the relatively short wavelength region of 510 530 mp. of the green region is raised and in which there is no increase of dye contamination and no lowering of sensitivity due to the coexistence of a coupler. This object can be accomplished by the use of a supersensitized silver halide photographic emulsion wherein at least one sensitizing dye represented by the following General Formula I and at least one sensitizing dye represented by the following General Formula II is added to the emulsion:

General Formula I l 1'12 N ZI. I /COH=CHOH=O J :22 .1 Q l )ul R3 R4 in which R R R and R represent alkyl groups, at

least one of R and R being an alkyl group having a sulfo group; Z and Z represent the non-metallic atoms necessary to complete a benzimidazole nucleus; X represents an acid anion group and p represents an integer of 1 or 2, p being 1 when said dye forms an intermolecular salt.

General Formula H 3 DESCRIPTION OF THE PREFERRED EMBODIMENTS According to this invention, the spectrally sensitized silver halide photographic emulsion can advantageously be used in combination with the oxacarbocyanine dye disclosed in Japanese patent publication No. 4936/68 or with the hemicyanine dye disclosed in Belgian Patent No. 724,467.

In R R R R and R the alkyl groups may be, for example, methyl, ethyl propyl, acetoxypropyl, hydroxyethyl, allyl, benzyl, 'y-sulfopropyl, 'y-sulfobutyl, 5-sulfo butyl, 2-(3-su1fopropoxy) ethyl, 2-[2-(3-sulfopropoxy) ethoxy] ethyl or Z-hydroxy-l-sulfopropyl groups. Examples of X and X are chlorine, bromine, iodine, perchlorate, thiocyanate, p-toluene sulfonate, benzenesulfonate, methyl sulfonate and ethyl sulfate ions.

'One feature of the invention lies in the substituent of the l -forming nucleus in Formula II. The substituent f the invention is useful for raising the sensitivity in the 515-530 my range in connection with the property of the dye I aggregate and to obtain a suitable spectral sensi tivity. The dye of Formula I is the well-known benzimidazolocarbocyanine. In particular, the nucleus substituent of said benzimidazole includes those mentioned in Japanese patent publication Nos. 4936/68, 2884/68, 2530/69 and 16589/69.

b 1Examples of the compounds of this invention are shown e ow:

2H5 CzHr 1 I c1 c1 c-on=on-cn=o 01 1 \N 01 fiicnzomonms a zCHz )z( 2)z a z s)a (IB) (Jr H5 2: 5

O /o=on-oH=cH-c\ I) 01 on,

din, (cmnsoi 1c (pmnocoom am N\ /N\ C1 /CCH=OH-CH=C c1 c1 63 N N rmasoa Ds a Q (ID) 2 5 (EH5 01 01 i OCH=GHCH=C I SO 1 l N I 011 03 02H:

IA (1 H3O s 011:0 l \N/ GOOCzHs Qa I 4 (11B) um /s \g/ CH=O\ -ooon I zHu G OOCH; zHs N (an) cm /s..

g}, CH-=0 QC 000 H (1 1315 N z s zh oa The compounds of Formula I can readily be synthesized by known methods, such as those disclosed in United States Pat. Nos. 2,912,329 and 2,778,823 and Japanese patent publication Nos. 7828/63, 27166/67, 4931/68, 13823/68, 14497/68, 16589/69', etc.

The compounds of Formula II can also readily be synthesized by known methods such as those disclosed in United States Patent No. 2,503,776. A typical method for the synthesis of compound HA is as follows: 850 mg. of 6 methyl-Z-ethylmercapto-l-ethylquinolinium ethyl sulfate and 800 mg. of anhydro-S-carbomethoxy-Z-methyl- 3 (y-sulfopropyl)-benzothiazolium hydroxide are dissolved in ml. of ethyl alcohol, to which is added 3.5 ml. of triethylamine, and heated for 4 hours with refluxing. After the reaction, the solvent is removed and the residue is treated with ether and then with acetone to yield a crude crystal. When this crude crystal is recrystallized from ethyl alcohol, 400 mg. of an orange crystal having a melting point of 300 C. and a is obtained. The Other sensitizing dyes of this invention can be synthesized in a similar manner.

The charatceristic; of the sensitizing dyes mentioned as typical examples of Dye type II are shown below:

Dye No. M.P. 0.)

HA. 300 or more IIB .-do

The dye used in this invention may be added to the emulsion in the form of a solution in water or in a watersoluble organic solvent such as methanol, ethanol, pyridine, acetone or Cellosolve. The sensitizing dyes represented by Formulae I and II may be added as individual solutions or as a mixed solution. Dissolving may be effected by ultrasonic wave agitation. The amount of each dye may be varied with the emulsion employed. Ordinarily, the amount of both dyes is preferably from 1X10- mole to 1X10 mole per 1 mole of silver halide. The weight proportion of the dye of Formula I to the dye of Formula II varies from :1 to 1:2, and preferably from 4:1 to 2: 1. This proportion may also be varied depending on the use of other additives in the emulsion.

The silver halide emulsions which may be used are, for example, silver iodobromide, silver bromide and silver chlorobromide. In particular, a silver iodobromide emulsion is advantageous to use, because its particle size is not particularly restricted. Gelatino-silver halide emulsions are mainly used, but binders other than gelatin may, of course, be used, for example, polyvinyl alcohol, alginate polymers, polyvinyl imidazole, polyvinylpyrrolidone and mixtures thereof with gelatin.

The silver halide emulsion of the present invention is coated onto a suitable support, depending on its use, for example, baryta paper, cellulose triacetate film, polyethylene terephthalate film, plastic films resin-coated paper or synthetic paper.

The following examples illustrate the present invention in more detail. and are not intended to limit the same.

EXAMPLES 50 g. of 1 phenyl-3-[3-(2,4-ditertiaryamylphenoxyacetamide)benzoamidel-S-pyrazolone dissolved with heating in 100 m1. of dibutyl phthalate was added to 1000 ml. of a 10% aqueous solution of gelatin, to which 50 ml. of a 5% aqueous solution of sodium alkylbenzenesulfonate was then added. This was emulsified by a high speed revolving mixer. The resulting emulsion is called a coupler dispersion.

1 kg. of a silver iodobromide emulsion prepared in a conventional manner (amount of silver: 0.25 mole; iodine content: 4.0 mole percent) was placed in a beaker and dissolved in a bath at 40 C. Predetermined amounts of the sensitizing dyes as shown in Table I were added there- TABLE I to with agitation and allowed to stand for 10 minutes. 400 g. of the magenta coupler dispersion was then added with agitation and allowed to stand for 1 hour. The resulting emulsion was applied to a support of cellulose triacetate film to give a dry film thickness of 7 microns on the base. A sample of green-sensitive photographic material was thus obtained.

The sample was cut into strips and subjected to light wedge exposure through a yellow filter of No. K-12 (trademartk) using a sensitometer having a light source color temperature of 5400 K. It was then developed at 20 C. for 12 minutes with the following developer composition:

G. N,'N-diethyl-p-aminoaniline sulfate 2.0 Sodium sulfite 2.0 Sodium carbonate (monohydrate) 50.0 Hydroxylamine hydrochloride 1.5 Potassium bromide 1.0

Water to make 1 liter.

Thereafter, the sample was passed through a first fixing solution, a bleaching solution and a second fixing solution and washed with water to obtain a magenta image. After drying, the green filter density was measured with an S-type (trademark) densitometer manufactured by Fuji Photo Film Co., Ltd. Thus, a characteristic curve was obtained from which the sensitivity at the optical density fog+()..20 was determined, is shown in Table 1.

Water to make 1 liter.

Amount used, m1. (mol cone.)

Amount used, ml. (mol cone.)

Dye

Dye used Example No.- used (IIE) 20(5X10'i) A) (HA) yellow filter sensitivity Maximum sensitizing wavelength y) Relative 7 What is claimed is: 1. A spectrally sensitized silver halide photographic emulsion containing at least one sensitizing dye represented by the following first formula:

wherein R R R and R each represent alkyl groups, at least one of said R and R being an alkyl group having a sulfo group Z and Z represent the non-metallic atomic groups necessary to complete a benzimidazole nucleons; X represents an acid anion and p represents an integer of 1 or 2, p being 1 when said dye forms an intermolecular salt; and at least one sensitizing dye represented by the following second formula:

wherein 2;, represents the atomic group necessary to complete a quinoline nucleus; Z represents the non-metallic atomic group necessary to complete a benzothiazole or benzoselenazole nucleus substituted by a carboxylic acid, an alkoxycarbonyl, a carbamoyl, or an acyl group; R

and R represent alkyl groups, at least one of said R wherein R and 2;, have the same meaning as in claim 1, wherein R represents a methyl or ethyl group, and wherein n represents 2, 3 or 4.

4. A spectrally sensitized silver halide photographic emulsion containing a sensitizing dye represented by the formula:

iomcrnomcmnsoi and at least one sensitizing dye represented by the following formula:

COOR

wherein R R Z and n have the same meaning as in claim 3.

5. A spectrally sensitized silver halide photographic emulsion containing a sensitizing dye represented by the formula:

9/0 -C H=G HCH=C\ Q C1 C1 9115 3 (cums osnmciua wherein n, is an integer from 1 to 5, and at least one sensitizing dye represented by the following formula:

wherein R R Z and n have the same meaning as in claim 3.

6. The emulsion of claim 1 further containing a magenta coupler.

7. The emulsion as in claim 1 wherein the sensitizing dyes represented by the first and second formulae are incorporated in said silver halide emulsion in an amount of from 1X 10 mole to 1 X 10- mole per 1 mole of silver 'halide in said emulsion.

8. The emulsion as in claim 1 wherein the weight ratio of the sensitizing dye represented by the first formula to the sensitizing dye represented by the second formula varies from 10: 1 to 1:2.

9. A photographic light-sensitive element comprising a l (CHaCHgO) ;(GH S OsHN (C2116):

9 10 support having thereon at least a layer containing the 3,255,012 6/1966 Glockner et a1 96 132 silver h lide emulsion f claim 1. 3,348,949 10/ 1967 Bannert et a1. 96-424 References Cited J. TRAVIS BROWN, Primary Examiner 5 UNITED STATES PATENTS Us CL XIR- 2,503,776 4/1950 Sprague 96--132 2,701,198 2/1955 Carroll et a1 96-124 

